Questions about the true identity of the Zodiac Killer have been raised yet again with the release of Baton Rouge businessman Gary L. Stewart's new book, "The Most Dangerous Animal of All." In the book, which he wrote with true crime writer Susan Mustafa, Stewart makes the case that his biological father -- Earl Van Best Jr. -- was the infamous killer who took at least five lives in northern California decades ago.

Stewart insinuated that the San Francisco Police Department, which led the hunt for the murderer who teased local publications about his identity so many years ago, might have ignored evidence when Stewart brought it to their attention. Since news broke of the new book, the police department has issued a statement declining to comment.